Detection rules › Splunk

Conhost.exe Kernel call (Sysmon)

Group by
_time, host
Source
github.com/anvilogic-forge/armory

conhost. exe ForceV1 asks for information directly from the kernel space, conhost connects to the console application. Usecase Identifies potentially suspicious Conhost execution paired with additional processes

MITRE ATT&CK coverage

References

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 1: Process creation

Rule body

id: '5541.17145'
title: Conhost.exe Kernel call
description: 'conhost. exe ForceV1 asks for information directly from the kernel space,
  conhost connects to the console application. Usecase Identifies potentially suspicious
  Conhost execution paired with additional processes. - Software Association: Trojan.Killdisk/HermeticWiper,
  Snatch'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` ("EventCode=1" OR "<EventID>1<")
  NOT (TERM(usoclient.exe) OR TERM(devicecensus.exe) OR TERM(ProgramData) OR "Program
  Files" OR "wmiprvse.exe") | regex process="^\S+\s" | table _time, host, user, process,
  process_*, parent_*, signature_id | bin span=1s | stats values(*) as * by _time,
  host | regex process="conhost.exe 0xffffffff -ForceV1"| where mvcount(process)>1 '
techniques:
- defense-evasion:indirect command execution
- execution:command and scripting interpreter
- defense-evasion:exploitation for defense evasion
technique_id: 
- T1202
- T1059
- T1211
data_category:
- Windows Sysmon
references:
- https://medium.com/@clermont1050/covid-19-cyber-infection-c615ead7c29

Stages and Predicates

Stage 1: search

`get_endpoint_data` `get_endpoint_data_sysmon` ("EventCode=1" OR "<EventID>1<") NOT (TERM(usoclient.exe) OR TERM(devicecensus.exe) OR TERM(ProgramData) OR "Program Files" OR "wmiprvse.exe")

Stage 2: regex

| regex process="^\S+\s"

Stage 3: table

| table _time, host, user, process, process_*, parent_*, signature_id

Stage 4: bucket

| bin span=1s

Stage 5: stats

| stats values(*) as * by _time, host

Stage 6: regex

| regex process="conhost.exe 0xffffffff -ForceV1"

Stage 7: where

| where mvcount(process)>1

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
processregex_match
  • "^\S+\s" corpus 2 (splunk 2)
  • "conhost.exe 0xffffffff -ForceV1" corpus 2 (splunk 2)
field:"CommandLine" kind:regex_match

Search terms

These SPL tokens match against raw event text.

StageTerm
1"EventCode=1"
1"<EventID>1<"